Issues with Qualification of Radiographic NDE Techniques

This assessment examined limitations of X-ray radiography in detecting high-cycle fatigue cracks, focusing on three key issues: methodology for qualifying double-wall radiography, the impact of etching on probability of detection (POD), and the effect of X-ray incidence angle on crack detectability. Comparison of computed radiography (CR) and digital radiography (DR) and effectiveness in meeting NASA inspection requirements was facilitated using historical documentation review, simulation, and testing. This study established how trends documented for CR related to DR using testing and simulation for various beam angles, single versus double-wall variations, and on typical COPV wall materials and configurations. The results also highlighted some of the deficiencies in the current NASA STD-5009 and recommends reexamination of that document with updated POD methods to accommodate newer radiographic methods.